U.S. patent number 4,554,137 [Application Number 06/541,776] was granted by the patent office on 1985-11-19 for enrichment of minerals by flotation and collector agents employed for this purpose.
This patent grant is currently assigned to Societe Nationale Elf Aquitaine (Production). Invention is credited to Patrice Guesnet, Jacques Maurice, Guy Muller, Pierre Tozzolino.
United States Patent |
4,554,137 |
Maurice , et al. |
November 19, 1985 |
Enrichment of minerals by flotation and collector agents employed
for this purpose
Abstract
Process of enrichment of minerals by flotation by means of a
collector comprising a thio-compound, the thio-compound being a
straight or branched dialkyl or dialkenyl polysulphide.
Inventors: |
Maurice; Jacques (Pau,
FR), Guesnet; Patrice (Pau, FR), Tozzolino;
Pierre (Morlaas, FR), Muller; Guy (Monein,
FR) |
Assignee: |
Societe Nationale Elf Aquitaine
(Production) (FR)
|
Family
ID: |
9278233 |
Appl.
No.: |
06/541,776 |
Filed: |
October 13, 1983 |
Foreign Application Priority Data
|
|
|
|
|
Oct 13, 1982 [FR] |
|
|
8217128 |
|
Current U.S.
Class: |
423/26; 209/166;
209/167 |
Current CPC
Class: |
B03D
1/012 (20130101); B03D 2203/02 (20130101); B03D
2201/02 (20130101) |
Current International
Class: |
B03D
1/012 (20060101); B03D 1/004 (20060101); B03D
001/02 () |
Field of
Search: |
;75/2,117 ;423/26
;209/167,166 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rutledge; L. Dewayne
Assistant Examiner: Kastler; S.
Attorney, Agent or Firm: Ostrolenk, Faber, Gerb &
Soffen
Claims
We claim:
1. Process of enrichment of minerals by flotation with the aid of a
collector consisting essentially of a polysulphide having two
aliphatic hydrocarbon groups, wherein these groups are alkyl or
alkenyl, one group having 2 to 12 carbon atoms and the other having
6 to 12 carbon atoms, and wherein the polysulphide is in the form
of a solution in a solvent selected from the group consisting of
alcohol, carbon disulphide, dimethyl sulphoxide, benzene and
kerosene.
2. Process according to claim 1 wherein the solvent is ethyl
alcohol.
3. Process according to claim 2 wherein the collector is selected
from the group consisting of dihexyl disulphide,
lauryl-ethyl-disulphide, dilauryl disulphide, dihexyl trisulphide,
dilauryl trisulphide and dilauryl pentasulphide and wherein the
amount of collector per ton of mineral is 0.05 to 1.5 mole.
4. Process according to claim 1 wherein the polysulphide is in the
form of emulsion with a liquid surfactant.
5. Process according to claim 4 wherein the liquid surfactant is
selected from the group consisting of polyol, polyethoxylated
alkylphenol, petroleum sulfonate, polyalkoxylated mercaptan, ester
of polyoxyalkylene fatty acid and ester of sorbitan.
6. Process according to claim 5 in which the collector is selected
from the group consisting of di-tert dodecyl pentasulphide, di-tert
dodecyl trisulphide, di-tert nonyl trisulphide and di-tert nonyl
pentasulphide, the surfactant is polyoxyethylene alkylphenol and
the amount of collector per ton of mineral is 0.05 to 1.5 mole.
7. Process according to claim 1 wherein 0.05 to 1.5 mole of the
collector in the form of a solution or emulsion is employed and
wherein the collector is selected from the group consisting of
di-tert dodecyl pentasulphide, di-tert dodecyl trisulphide, di-tert
nonyl trisulphide, di-tert nonyl pentasulphide, di-hexyl
disulphide, di-lauryl-disulphide, lauryl-ethyl-disulphide, di-hexyl
trisulphide, dilauryl trisulphide, and dilauryl pentasulphide.
Description
The present invention relates to the enrichment of minerals by
flotation with organic collectors constituted by thio-compounds. It
relates more particularly to the treatment of minerals based on
oxides and sulphides of heavy metals.
Compounds containing sulphur in their molecules have been
successfully employed in the flotation technique: this is
particularly the case with the alkali metal alkyl xanthates, which
are among the best collectors known at present. However, alkyl
mercaptans are also regarded as good collectors, particularly
C.sub.12 to C.sub.16, which--despite their low solubility in
water--have been advantageously utilized, when emulsified with
surfactant compounds.
The present invention is based on the discovery that the collector
properties of a thio-compound can be intensified by a certain
accumulation of sulphur atoms in the molecules of these compounds.
Thus, it has been found that dialkyl polysulphides can give better
results than the corresponding mercaptans; this is theoretically
surprising, because polysulphides have a molecular structure
containing two lipophilic chains. This fact is all the more
unexpected as the alkyl polysulphides higher than C.sub.8 are even
less soluble in water than the mercaptans.
The process according to the invention consists in effecting the
flotation of the mineral or minerals in a general manner known per
se, but with at least one di-hydrocarbyl polysulphide as a
collector or in conjunction with a collector of the known type, the
one or more polysulphides being represented by the formula:
where R and R' are the same or different and are alkyl or alkenyl
groups, which can carry substituents, and x is a number having an
average value of 2 to 8.
The substituents of the hydrocarbon groups R and/or R' can be other
aliphatic, cyclo-aliphatic or aryl radicals, halogens, nitriles or
functional groups, for example OH, -COOH, NO.sub.2, CONH.sub.2,
esters, carbonyls etc. Functional substituents giving affinity with
water are particularly favourable.
In practice, the groups R and/or R' are generally C.sub.1 to
C.sub.18, straight or branched, and particularly C.sub.4 to
C.sub.12.
A mode of preparation of such polysulphides is known, which
consists in treating for example the corresponding mercaptan with
sulphur, in the presence of an amine as catalyst, according to the
reaction:
This process in fact provides a mixture of polysulphides having
various numbers of S atoms, x thus being an average of these
numbers.
Although starting with C.sub.8, the polysulphides according to the
invention are practically insoluble in water, they can be
introduced into the mineral pulp to be treated in the form of a
solution in a solvent, or as an emulsion or as an extremely fine
dispersion. Thus, the polysulphide can be employed in solution in
alcohol, carbon disulphide, dimethyl sulphoxide, benzene, kerosene,
oil or other appropriate solvent. The emulsion can be produced by
mixing with a surfactant liquid, such as a polyol or a
polyethoxylated alkyl-phenol, a petroleum sulphonate, a
polyalkoxylated mercaptan, an ester of a polyoxyalkylene fatty acid
or of sorbitan, etc. As regards the aqueous or other dispersion, it
can be obtained by wet mircronisation.
The molar proportions of the new collectors according to the
invention employed in flotation are the same as those of the known
technique, that is generally about 0.05 to 1.5 and, more
particularly, 0.1 to 0.25 mole per tonne of mineral.
The Examples which follow illustrate the invention
non-limitatively.
EXAMPLES 1 to 6
A series of flotation tests is effected with a sulphide mineral of
copper obtained from the South African mine at Palabora, containing
0.45 to 0.48% Cu. 600 g of this mineral is ground to a fineness
such that 76% of the powder passes through a screen having 148
micron meshes.
After adding the necessary adjuvants, the product is subjected to
flotation for 20 minutes at pH 7.5, in a 2.5 liter laboratory cell
of the Minemet M 130 type, in the presence of
methyl-isobutyl-carbinol as a wetting agent added at the rate of 25
g per tonne of mineral.
The collectors are introduced in the form of mixtures of 57.5% by
weight of the thio-compounds with 42.5% of the surfactant,
polyoxyethylene nonyl phenol, known commercially under the name
"SIMULSOL 730". They are, on the one hand, (Examples 1 and 2) the
mercaptans usually used in flotation and, on the other hand,
(Examples 3 to 6) polysulphides according to the invention; their
proportion in millimoles per tonne of mineral is indicated in the
results Table which follows. The last two columns in this Table
indicate the percentage Cu content in the concentrate obtained, as
well as the percentage of Cu recovered.
______________________________________ Ex. Millimoles Conc. % Cu
No. Collector per tonne % Cu recovered
______________________________________ 1 n-dodecyl-mercaptan 173
10.4 30.4 2 tert.dodecyl-mercap- " 9.4 61.0 tan 3 di-tert.dodecyl-
" 14.5 66.7 pentasulphide 4 di-tert.dodecyl- 124 13.3 48.0
pentasulphide 5 di-tert.dodecyl-tri- 173 13.7 20.5 sulphide 6
di-tert.nonyl-tri- " 11.6 19.7 sulphide 7 di-tert.nonyl-penta- "
12.7 58 sulphide ______________________________________
Thus the concentrations of Cu obtained are always better with the
polysulphides than those given by known collectors. Also, in equal
molar proportions, the pentasulphides permit a recovery of copper
comparable or superior to that of the mercaptans.
EXAMPLES 7 to 14
Flotation tests are effected with each of the minerals designated
in the results Table by:
CHAL. --for chalcopyrite,
GAL. --for galena
BL. --for blende and
PYR. --for pyrites.
265 ml of water, 1 g of fine powder of the mineral and
3.times.10.sup.-4 g of the collector to be tested, per liter, are
introduced into a cell; this collector is utilized in the form of a
1% solution in ethanol.
The Table below gives the percentage of each mineral recovered as
the product of the flotation.
______________________________________ Ex. % of mineral recovered
No Collector CHAL. GAL. BL. PYR.
______________________________________ 8 Dihexyl-disulphide 94 88
84 90 9 Lauryl-ethyl-di- 92 -- 91 -- sulphide C.sub.12 H.sub.25
SSC.sub.2 H.sub.5 10 Dilauryl-disulphide 88 -- 89 87 C.sub.12
H.sub.25 SSC.sub.12 H.sub.25 11 Dihexyl-trisulphide 92 87 76 88
C.sub.6 H.sub.13 SSSC.sub.6 H.sub.13 12 Dilauryl-trisulphide 95 91
73 84 C.sub.12 H.sub.25 SSSC.sub.12 H.sub.25 13
Dilauryl-pentasulphide 88 93 69 79 C.sub.12 H.sub.25 S.sub.5
C.sub.12 H.sub.25 14 n-Dodecyl-mercaptan 81 87 64 73
______________________________________
It can be seen that the polysulphides of Examples 8 to 13 give
bettwer results than those given by n-dodecyl mercaptan (Example
14) currently employed at the present time.
EXAMPLES 15 to 20
Assey on chalcopyrite with 3.times.10.sup.-4 g/l of collector.
______________________________________ Ex. Results % No. Collector
pH 7 8 9 10 ______________________________________ 15 C.sub.6
H.sub.13 S.sub.2 C.sub.6 H.sub.13 46% 45% 45% 42% 16 C.sub.12
H.sub.25 S.sub.2 C.sub.12 H.sub.25 54% 49% 47% 46% 17 C.sub.12
H.sub.25 S.sub.2 C.sub.2 H.sub.5 44% 44% 44% 37% 18 C.sub.6
H.sub.13 S.sub.3 C.sub.6 H.sub.13 48% 43% 41% 40% 19 t C.sub.12
H.sub.25 S.sub.3 tC.sub.12 H.sub.25 88% 86% 86% 88% 20 t C.sub.12
H.sub.25 S.sub.5 tC.sub.12 H.sub.25 85% 85% 85% 85%
______________________________________
It can be seen that when the collector has two S atoms and six or
less carbon atom alkyl groups, the results are poorer.
* * * * *